U.S. patent number 6,522,381 [Application Number 09/410,181] was granted by the patent office on 2003-02-18 for display device having pointer and electrooptic display.
This patent grant is currently assigned to Mannesmann VDO AG. Invention is credited to Peter Brandt.
United States Patent |
6,522,381 |
Brandt |
February 18, 2003 |
Display device having pointer and electrooptic display
Abstract
A invention relates to a display device, in particular for a
motor vehicle, having a pointer, a scale and an electrooptic
display, it being possible to represent measured values on the
scale in an analog fashion using the pointer, and at least one area
of the electrooptic display being arranged along the movement path
of the pointer. In order to provide a high level of information
density while simultaneously making the display easy to read, the
electrooptic display has a first display field which runs along at
least one section of the movement path of the pointer and has
display segments which can be actuated, and a second display field
which can be actuated in an unrestricted way.
Inventors: |
Brandt; Peter (Aschaffenburg,
DE) |
Assignee: |
Mannesmann VDO AG (Frankfurt,
DE)
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Family
ID: |
7883288 |
Appl.
No.: |
09/410,181 |
Filed: |
September 30, 1999 |
Foreign Application Priority Data
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Oct 2, 1998 [DE] |
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198 45 579 |
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Current U.S.
Class: |
349/142;
116/62.1; 368/242; 349/11; 345/5; 116/62.4; 116/62.3 |
Current CPC
Class: |
G01C
21/265 (20130101); G02F 1/13471 (20130101); G01C
21/3632 (20130101); G01D 7/002 (20130101); G01P
1/08 (20130101); B60K 2370/154 (20190501); B60K
2370/6985 (20190501) |
Current International
Class: |
G02F
1/13 (20060101); G02F 1/1347 (20060101); G01D
7/00 (20060101); G01C 21/34 (20060101); G01C
21/36 (20060101); G01P 1/00 (20060101); G01P
1/08 (20060101); G02F 001/134 (); G01P
005/00 () |
Field of
Search: |
;349/11,142,83,77
;345/38,40,103,4,5 ;116/62.3,62.1,62.4 ;D10/98,124 ;D12/192
;368/82,83,84,240,241,242 ;968/575 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0415292 |
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Mar 1991 |
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EP |
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0672892 |
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Sep 1995 |
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EP |
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0708353 |
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Apr 1996 |
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EP |
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2007882 |
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May 1979 |
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GB |
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2268304 |
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Jan 1994 |
|
GB |
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WO9312453 |
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Nov 1992 |
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WO |
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Primary Examiner: Dudek; James
Assistant Examiner: Schechter; Andrew
Attorney, Agent or Firm: Farber; Martin A.
Claims
I claim:
1. A display device, in particular for a motor vehicle, having a
pointer, a scale and an electrooptic display, it being possible to
represent measured values on the scale in an analog fashion using
the pointer, and at least one area of the electrooptic display
being arranged along the movement path of the pointer, wherein said
electrooptic display (4) has a first display field (5) which runs
along at least one section on the movement path (7) of the pointer
(2) and has display segments (9) which are actuatable, and a second
display field (6) which is actuatable in an unrestricted way; and
wherein the electrooptic display (4) has a multilayer liquid
crystal display (13) having on a substrate at least two electrode
layers (20, 21) which are electrically separated from one another
and actuatable independently.
2. The display device as claimed in claim 1, wherein the first
display field (5), with said display segments (9) which are
actuatable, can be represented with a first of the electrode layers
(20), and the second display field (6), which is actuatable in an
unrestricted way, can be represented with the second electrode
layer (21).
3. The display device as claimed in claim 1, wherein said
electrooptic display (4) has a liquid crystal display (10; 11, 12;
13).
4. The display device as claimed in claim 3, wherein of said liquid
crystal display (10; 11, 12; 13) is a TN or STN display.
5. The display device as claimed in claim 1, wherein the second
display field (6), which is actuatable in an unrestricted way, is a
dot matrix field which is actuatable using a multiplex method.
6. The display device as claimed in claim 1, wherein the second
display field (6), which is actuatable in an unrestricted way, is
actuatable using an anti-aliasing method.
7. The display device as claimed in claim 1, wherein light
characters are representable on a dark display area using the
electrooptic display (4).
8. The display device as claimed in claim 7, wherein nonselected
display elements are actuatable with an actuation voltage
(undershoot range) which has a minimum transmission.
9. The display device as claimed in claim 8, wherein the movement
path (7) of the pointer (2) describes a circular arc segment.
10. The display device as claimed in claim 1, wherein a travel
speed is displayable with the pointer (2), and wherein a set value
of a speed regulating system is representable by actuating at least
one display segment (9) of the first display field (5).
Description
FIELD AND BACKGROUND OF THE INVENTION
The invention relates to a display device, in particular for a
motor vehicle, having a pointer, a scale and an electrooptic
display, it being possible to represent measured values on the
scale in an analog fashion using the pointer, and at least one area
of the electrooptic display being arranged along the movement path
of the pointer.
Such display devices are known and are principally used in motor
vehicles to display a travel speed or an engine speed. The
electrooptic display has in such cases display segments with a
defined, nonvariable shape. It is therefore not possible to
represent any kind of information or graphics as desired.
Other known display devices having an analog pointer-type round
instrument and a display over which said pointer passes in order to
represent variable information have a large scale face which can be
actuated, it being possible to actuate in a variable fashion all
the display elements including the scale divisions and to represent
them on the display. The size of the display face which can be
actuated is a direct measurement of the fabrication costs of the
display and thus of the display instrument, as a result of which
these known display instruments are very expensive. Furthermore,
the representation on the display is limited to a display mode
which is made up of individual, approximately quadratic picture
elements, as a result of which arcuate elements can only be
represented in an approximated way and with incremental jumps which
make the display more difficult to read. This is particularly
disadvantageous in the case of display elements which are assigned
to the (round) scale.
SUMMARY OF THE INVENTION
The invention is therefore based on the object of designing a
display device of the aforementioned type in such a way that it
provides an analog representation of measured values using a
pointer instrument and an unlimited way of presenting information
including displays on the electrooptic display which correspond to
the scale, while at the same time the fabrication costs for the
display device are low.
This object is achieved according to the invention in that the
electrooptic display has a first display field which runs along at
least one section of the movement path of the pointer and has
display segments which can be actuated, and a second display field
which can be actuated in an unrestricted way.
Thus, different types of representations can easily appear
independently of one another on the two display fields. For
example, the first display field can have defined display segments
which are adapted to the geometry of the scale and of the movement
path of the pointer. The first display field ensures that the
measured values which are represented on the scale using the
pointer, and further information which is visualized by actuating
the display segments, can be read easily and reliably. The number
of display segments of this display field may be comparatively low
here, because only a limited number of geometries have to be
represented. The adaptation of the display segments to the
necessary geometries avoids undesired step increments in the
representation. On the other hand, the second display field, which
can be actuated in an unrestricted way, serves for the unrestricted
representation of information. Here, for example graphics, such as
route indications of an application system, video sequences or, in
certain cases, warning signals, can be displayed. In this way, the
display device according to the invention combines the possibility
of representing various types of information in an unrestricted way
with an instrument which can be read easily and reliably. This
implements a high level of information density with, at the same
time, a display which is easy to read.
It would be conceivable to use a cathode ray tube or a vacuum
fluorescent display for the electrooptic display. However, the
display device can be fabricated particularly cost-effectively and
in large numbers if the electrooptic display advantageously has a
liquid crystal display. In particular, when used in motor vehicles,
the liquid crystal display provides further advantages, because it
has only a low electric power drain and, by virtue of its flat
design, requires only a small installation space.
The electrooptic display can be fabricated cost-effectively and
easily if, in accordance with another advantageous development of
the invention, the liquid crystal display is a TN or STN display.
Such displays are additionally very operationally reliable and, in
particular, STN displays are easy to read even with extreme viewing
angles.
According to another advantageous development of the invention, the
display has the first display field with display segments which can
be actuated, and the second display field, which can be actuated in
an unrestricted way, in the same display plane, with the result
that, on the one hand, the number of production processes necessary
to fabricate the display is low and, on the other hand, it is
ensured that the two display fields can be read simultaneously in
an easy, precise way, free from parallax.
The actuation of the electrooptic display can advantageously been
simplified if it has two liquid crystal displays which are arranged
optically in series. The first display field with segments which
can be actuated is preferably arranged on a first of the liquid
displays and the second display field, which can be actuated in an
unrestricted way, is arranged on the second liquid crystal display.
In this way, the displays can be designed in a way which has
optimum adaptation to the different requirements, it being also
possible largely to prevent them influencing one another
electrically. In this way it is also easily possible to provide,
for example, a display with a first display field which is adapted
to a defined scale and has display segments which can be actuated,
and to select the liquid crystal display which is arranged
optically in series with said display and which has the second
display field which can be actuated in an unrestricted way, either
as a monochrome display or color display depending on the
individual wishes and requirements.
A way of representing information in a particularly unrestricted
way over a large area (for example to show a video film) which is
particularly attractive if there is no representation on the first
display field (for example when the vehicle is stationary), can
preferably be obtained if the display fields overlap at least
partially.
The necessary installation space for an electrooptic display which
has two liquid crystal displays which are arranged optically in
series is, according to another advantageous development of the
invention, particularly small if the electrooptic display has a
DSTN display.
A maximum, physical integration of the elements of the display can
be achieved if the electrooptic display advantageously has a
multilayer liquid crystal display having on a substrate at least
two electrode layers, which are electrically separated from one
another and can be actuated independently. Although it continues to
be possible to represent a plurality of display fields with such a
design, all that this requires is a single liquid crystal cell with
one front wall and one rear wall, each fitted with electrodes, a
liquid crystal substance being enclosed between the walls. In this
context it is particularly favorable, and simplifies the design, if
the first display field with display segments which can be actuated
can be represented with a first of the electrode layers and the
second display field, which can be actuated in an unrestricted way
can be represented with the second electrode layer.
A particularly wide variety of information can be represented in an
unrestricted way with the display device if the second display
field, which can be actuated in an unrestricted way is preferably a
dot matrix field which can be actuated using a multiplex method.
Despite the possibility of actuating a large number of picture
elements, the multiplex method requires only a comparatively low
amount of structural work for the display device.
According to another advantageous development of the invention, the
second display field, which can be actuated in an unrestricted way,
can be actuated using an anti-aliasing method. This provides image
smoothing which, in particular also when representing moving
images--leads to a clear display and thus one which can be read and
recognized better.
It is possible to conceive of representing dark characters on a
light background on the electrooptic display, but this makes the
display more difficult to read, in particular when there is low
ambient light the large background surface can have a dazzling
effect on a viewer. Since motor vehicles with display instruments
which cannot be read so well also have the direct effect of also
reducing traffic safety, such disadvantages must be avoided. It is
therefore particularly advantageous if light characters can be
represented on a dark display area using the electrooptic
display.
A particularly good contrast between the characters represented and
the rest of the display area forming the background of the display,
and between said characters and the nonselected characters is
advantageously achieved if nonselected display elements can be
actuated with an actuation voltage (undershoot range) which has a
minimum transmission. In this context, use is made of the effect
experienced in liquid crystal cells, according to which an
actuation voltage lying between an actuation voltage which gives
rise to a high level of transmission and a nonactuation voltage
which gives rise to a low level of transmission leads to a minimum
level of transmission of the liquid crystal cell.
The pointer of the display device may, for example, execute a
linear movement along a linear scale in order to display measured
values. However, such a display device is difficult to read because
the entire display region is difficult to perceive with one glance.
Rapid assessment, necessary in particular in motor vehicles, of the
relative magnitude of the displayed measured value is therefore
only possible with difficulty. It is therefore of particular
advantage if, according to another advantageous development of the
invention, the movement path of the pointer describes a circular
arc segment, and the entire display region of the pointer, together
with the position of the pointer, can be perceived in a very short
time.
According to another advantageous development of the invention, a
travel speed can be displayed with the pointer, and a set value of
a speed regulating system can be represented by actuating at least
one display segment of the first display field. In this way, a mark
or a band of display segments directly in the vicinity of the scale
and of the movement path of the pointer can be used to represent
the preset speed. Furthermore, important operational data of the
vehicle such as fault messages or navigation instructions can be
displayed on the second display field which can be actuated in an
unrestricted way. In this way, the display device according to the
invention provides a comprehensive way of representing information
which can be read and absorbed easily by a vehicle driver, the
possibility of him being distracted from the traffic situation
being thus reduced to a minimum, unavoidable level.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in more detail below with reference to
exemplary embodiments which are represented in the appended figures
of the drawings, in which
FIG. 1 shows a display device in a front view,
FIG. 2 shows a dial and display segments of the display device in a
front view,
FIG. 3 shows two liquid crystal displays of an electrooptic display
in a perspective view, and
FIG. 4 shows a multilayer liquid crystal display in a sectional
view.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a display device 1 which is a component of a
combination instrument (not further represented here). The display
device 1 has a circular-segment-shaped scale 3 on which a travel
speed of the motor vehicle can be represented by means of a pointer
2 which can be pivoted along a movement path 7. The pointer 2 is
embodied here as a disc pointer with transparent central region or
as a ring pointer, and it is driven by means of the circumference
of the disc or ring. The pointer drive is covered by a plate 24. An
electrooptic display 4 which has a liquid crystal display 10, of
which only a central area 8 is not covered by a dial 15 (FIG. 2)
which has the scale 3, is arranged in the central area formed
around the pivot axis of the pointer 2.
A first display field 5 with display segments 9, which can be
actuated, of the electrooptic display 4 runs along the movement
path 7 of the pointer 2. A preselected travel speed of a speed
regulating system is represented in the first display field 5,
which is formed by a belt of display segments 9. The start of the
belt composed of actuated display segments 9 with a scale value of
40 km/h means that the speed regulating system can be activated
starting from this lower limiting speed. The upper limiting value
of approximately 175 km/h represents the preselected travel
speed.
A further display field 6 of the electrooptic display 4 can be
actuated in an unrestricted way and shows a route indicator symbol
of a navigation system and an external temperature (+20.5.degree.
C.). In order to represent information in an unrestricted way, the
second display field 6 is embodied as a dot matrix with picture
elements which can be actuated individually. In a third display
field 25, arranged in the lower region of the display device 1,
there is a route display with an indication of the entire distance
(2456 km) which has been covered and the distance (24.6 km) which
has been covered from a selected point (for example the start of
the journey).
In order to clarify further, FIG. 2 shows the scale 3, which is
embodied in a conventional way as a dial 15 in the form of a
printed film, together with the fields 6, 25 which can be actuated
in an unrestricted way, and the display field 5 which has display
segments 9 which can be actuated. It is to be noted that the
display segments 9 are arranged in such a way that display values
between 0 and 260 km/h can be represented with them. Instead of the
band which is represented in FIG. 1 and is formed by actuated
display segments 9, it is also possible to actuate only individual
display segments 9 which display the preselected travel speed of
the speed regulating system. Moreover, the display segments 9 can
for example, also be used to display the engine speed of the
vehicle engine. In this case, not only the scale 3 but also a
further scale which indicates engine speed values are provided.
According to the exemplary embodiment shown in FIGS. 1 and 2, a
single liquid crystal display 10 is provided for the electrooptic
display 4. As a result, the display area of the second display 6
which can be actuated in an unrestricted way is limited to a region
which is not covered by the first display field 5. In order to
increase the image area of the second display field 6, if
representation is not necessary in the first display field (for
example when the vehicle is stationary or when the speed regulating
system is switched off), there is provision according to FIG. 3 for
a first liquid crystal display 11 and a second liquid crystal
display 12 for the electrooptic display to be arranged optically in
series.
The first liquid crystal display 11 has here a first display field
5 with display segments 9 which can be actuated, and the second
liquid crystal display 12 has a second display field 6, which can
be actuated in an unrestricted way and is formed by a dot matrix.
Electric connection and contact regions 26, 27 of the liquid
crystal displays 11, 12 are not illustrated here in detail. The
first liquid crystal display 11 is of particularly simple form
because only a small number of image segments can be actuated
directly. The second liquid crystal display 12 which is provided as
a dot matrix display is actuated using a multiplex method.
Instead of the two displays 11, 12 in FIG. 3, it is possible, as
illustrated in FIG. 4, to use a single multilayer liquid crystal
display 13 for the electrooptic display. The display 13 has
electrode layers 20, 21 which are provided on a front substrate 14,
separated from one another by means of an insulation layer 17 and
correspond to electrode layers 22, 23 which are mounted on a rear
substrate 16 and are electrically separated from one another by an
insulation layer 18. A liquid crystal substance 19 is enclosed
between the front substrate 14 and the rear substrate 16. Liquid
crystal substance which is located between respectively
corresponding first electrode layers 20, 22 and second electrode
layers 21, 23 can be actuated by applying voltage to selected
electrodes.
* * * * *